You need to get calories from somewhere, should it be from carbohydrate or fat?

Sunday, February 21, 2010

Physiological insulin resistance: Dolphins

This article was sent to me by Stan, and it's interesting on many levels. At the most basic is the gross error in the description of the management of diabetes. This is what the article says:

"In diabetic people, chronic insulin resistance means having to carefully control blood glucose, usually with a diet low in sugar, to avoid a variety of medical complications."

NO NO NO NO NO!

Human diabetes is managed by a diet low in FAT. Ask any diabetologist.

The experience of Dr Dahlqvist encapsulates the monstrous medical approach to the use of low carbohydrate diets in diabetes.

I'm feeling a bit polite tonight for some reason so I won't mention what I think about low fat diets and diabetets. Perhaps I need a glass of wine.

This marine mammal researcher can see physiological insulin resistance in dolphins and see that it is PHYSIOLOGICAL. The difference between a healthy dolphin and a healthy human is minimal (can she see that too?). We humans "do" physiological insulin resistance. But she and her collaborators cannot see that there is a difference between physiological insulin resistance and breaking your liver by living on soda and bagels to get pathological insulin resistance... As she says:

"If we started feeding dolphins Twinkies, they would have diabetes."

Not true. Their insulin resistance would go as they switched on carbohydrate metabolism in their muscles. It would take several years of Twinkies to cause diabetes. Like humans. We're fine for the first few hundred/thousand Twinkies. Then we break.

EDIT: Being in the UK I hadn't realised how small Twinkies are. Let's say 100,000 or so to break your liver...

But ultimately we humans need Twinkies to survive. We must eat them to remain happy and feel part of normal society. Imagine a teenager saying no to a Twinkie, just because they are diabetic! No, we must help people to eat Twinkies while diabetic, so we MUST research the "fasting gene" which is abnormally activated in human diabetes. And develop a drug to turn it off, of course.

BTW the activator of the fasting gene will turn out to be palmitic acid. What other messenger would you use to suggest that there is a fasting state? So we're back to using Palmitofake and a continuous supply of Twinkies.

The title says "Dolphins have diabetes off switch"

No, they do not. There is no off switch for a broken liver. Unbroken dolphins are just behaving like unbroken humans. They turn off physiological insulin resistance when carbohydrate becomes available, even if that carbohydrate come from fish via gluconeogenesis. It's simple and it's NOT diabetes.

Sigh.

Peter

There is potentially a whole load more posts from this link, follow up depends on all sorts of things...

Studies of carnivore glucose metabolism in the context of lactation are rare. We would expect that the lower carbohydrate diet of carnivores would have important impacts on glucose metabolism; however, some studies do suggest that the high protein diet of carnivores may be associated with impaired ability for glucose clearance. Penguins (Chieri et al., 1972), barn owls (Myers and Klasing, 1999), rainbow trout (Palmer and Ryman, 1972), white sturgeon (Hung, 1991) and American alligators (Coulson and Hernandez, 1983) exhibited reduced glucose clearance when compared to omnivores. We are aware of no similar studies in wild mammalian carnivores. --------------------------------

I leave it to wiser heads to work this into an eventual cure for diabetes.

Chainey, I wonder if they are doing OGTTs on them? Sports drinks will be next. They already get iron overload in zoos, I don't think we know about in the wild...

Hi ToddBS, wow! Then we could feed them Twinkies and they wouldn't need to feel socially excluded from the spectators!

HI Ellenwyo, I guess they're OK until they get caught...

donny, that's a bit complex for me too but it looks like most carniovores do insulin resistance. I'm a bit surprised that omnivores don't, but the shuttling back and forth between fasting and lactation without mentioning insulin makes it hard to follow!

Wild dolphins have random BGs around 100mg/dl, range 66 to about 120 max. Under extreme capture stress. That does not strike me as hyperglycaemic and it's another post to try and talk about that. I was wanting to get to photomicrographs of arteriosclerosis but stuff is getting in the way...

Indeed, the article’s description of the insulin resistant state of dolphins reminds me of a state of mild ketosis in humans, which many people enter at night, especially if their dinner was low in carbs (or if they had no dinner). Maybe they should have removed the word “diabetic” from: “The overnight changes in their blood chemistry match the changes in [diabetic] humans”.

It seems to me that dolphins have not access to carbs in any significant quantity in their habitat over evolutionary timescales. No fruits, berries, or tubers there, though for all I know maybe sea cucumbers are high carb. ;) How can dolphin lessons be applied to humans?

---------------------------------Recurrent obesity is beneficial in nature, as due to extensive fat depots, obese mammals can prolong phase II of fasting with stimulated fat oxidation and protein conservation, permitting extended survival during nutritional scarcity (5, 6). Due to finite food resources, wild animals practically never develop persistent obesity with comorbidities, but the situation becomes different under domestication. Thus, although the natural body condition of the European polecat is lean, it has the potential for extensive weight gain and obesity analogous to humans. The high fat-% (40%) of the farmed polecats probably results from excessive and prolonged positive energy balance (18) and limited physical activity (19, 20)—crucial aspects in human obesity, as well. Artificial selection for a large body size (21) may also be a causative factor. To the best of our knowledge, there exist no published data on the body adiposity of wild polecats, but it can be assumed that they would be considerably thinner. In fact, the estimated fat-% of 2 wild-caught males was 9.8% ± 6.5% in winter (Mustonen et al. unpubl. data)-----------------------------------

The body fat content of the American marten (Martes americana) averages <6% (13), but data are scanty for wild specimens of related species (14). This natural leanness can be lost in captivity, resembling the sedentary lifestyle of a significant part of the general population with overabundance of high-fat and high-carbohydrate foods and restricted exercise.--------------------------------

Those are both from here;http://ebm.rsmjournals.com/cgi/content/full/234/11/1287

If they can't even admit that there might be something special about carbohydrate metabolism that makes it particularly fattening in carnivores, besides just the calories, is there any hope?

Years ago, my roommate had a ferret. The thing was a blur. I couldn't see it becoming inactive unless something ruined its metabolism first.

Sorry, missed this one. I thing we are looking at basic survival related essential physiological processes here. I'm very willing to give a lot more credence to rat/doplphin studies than many LC bloggers as I'm looking for basic principles, with an eye to species specifics.

There are a couple of oddities about humans but generally we're just animals... Actually, having a well developed diving reflex is one oddity!

About Me

I am Petro Dobromylskyj, always known as Peter. I'm a vet, trained at the RVC, London University. I was fortunate enough to intercalate a BSc degree in physiology in to my veterinary degree. I was even more fortunate to study under Patrick Wall at UCH, who set me on course to become a veterinary anaesthetist, mostly working on acute pain control. That led to the Certificate then Diploma in Veterinary Anaesthesia and enough publications to allow me to enter the European College of Veterinary Anaesthesia and Analgesia as a de facto founding member. Anaesthesia teaches you a lot. Basic science is combined with the occasional need to act rapidly. Wrong decisions can reward you with catastrophe in seconds. Thinking is mandatory.
I stumbled on to nutrition completely by accident. Once you have been taught to think, it's hard to stop. I think about lots of things. These are some of them.

Organisation (or lack of it)!

The "labels" function on this blog has been used to function as an index and I've tended to group similar subjects together by using labels starting with identical text. If they're numbered within a similar label, start with (1). The archive is predominantly to show the posts I've put up in the last month, if people want to keep track of recent goings on. I might change it to the previous week if I ever get to time to put up enough posts in a week to justify it. That seems to be the best I can do within the limits of this blogging software!